Floquet Weyl fermions in circularly-polarised-light-irradiated three-dimensional stacked graphene systems

TL;DR

This paper demonstrates the creation of Floquet Weyl fermions in 3D stacked graphene under circularly polarized light, revealing their movement in momentum space and surface Fermi arcs, offering a new platform for Weyl fermion studies.

Contribution

It introduces a novel method to generate Floquet Weyl fermions in stacked graphene systems using circularly polarized light, with detailed phase diagrams and surface state analysis.

Findings

Weyl points can be created in irradiated graphene systems.

Weyl points move in momentum space as light frequency varies.

Fermi arcs are observed in surface Brillouin zones.

Abstract

Using Floquet theory, we illustrate that Floquet Weyl fermions can be created in circularly-polarised-light-irradiated three-dimensional stacked graphene systems. One or two semi-Dirac points can be formed due to overlapping of Floquet sub-bands. Each pair of Weyl points have a two-component semi-Dirac point parent, instead of a four-component Dirac point parent. Decreasing the light frequency will make the Weyl points move in the momentum space, and the Weyl points can approach to the Dirac points when the frequency becomes very small. The frequency-amplitude phase diagram is worked out. It is shown that there exist Fermi arcs in the surface Brillouin zones in circularly-polarised-light-irradiated semi-infinitely-stacked and finitely-multilayered graphene systems. The Floquet Weyl points emerging due to the overlap of Floquet sub-bands provide a new platform to study Weyl fermions.